On This Day dashboard widget follow up

src/js/_enqueues/admin/postbox.js

@@ -355,6 +355,21 @@
 				postboxes.setMetaBoxReordering( enabled );
 				postboxes.save_meta_box_reordering_state( enabled );
 			} );
+
+			$( '.wp-on-this-day-toggle' ).on( 'click.postboxes', function() {
+				var enabled = $( this ).prop( 'checked' );
+
+				postboxes.setOnThisDayDisplay( enabled );
+				postboxes.save_on_this_day_display( enabled );
+			} );
+
+			$( '#wp-on-this-day-posts-form button' ).on( 'click.postboxes', function( event ) {
+				event.preventDefault();
+				var enabled = '1' === $( this ).prop( 'value' );
+
+				postboxes.setOnThisDayDisplay( enabled );
+				postboxes.save_on_this_day_display( enabled );
+			} );
 		},
 
 		/**
@@ -495,6 +510,26 @@
 			}
 		},
 
+		/**
+		 * Enables or disables the On This Day display in the activity widget.
+		 *
+		 * @since 7.2.0
+		 *
+		 * @param {boolean} enabled Whether On This Day should be enabled.
+		 * @return {void}
+		 */
+		setOnThisDayDisplay: function( enabled ) {
+			var $onThisDayWidget = $( '#wp-on-this-day-posts' ),
+				$onThisDayList = $( '#wp-on-this-day-posts-list' ),
+				$onThisDayForm = $( '#wp-on-this-day-posts-form'),
+				$onThisDayScreenOption = $( '#wp-on-this-day-toggle' );
+
+			$onThisDayForm.hide(); // Always hidden once a choice is made.
+			$onThisDayWidget.toggle( enabled ).toggleClass( 'hidden', ! enabled );
+			$onThisDayList.toggle( enabled );
+			$onThisDayScreenOption.prop( 'checked', enabled );
+		},
+
 		/**
 		 * Saves the state of the postboxes to the server.
 		 *
@@ -560,6 +595,32 @@
 			);
 		},
 
+		/**
+		 * Saves the On This Day setting to the server.
+		 *
+		 * @since 7.2.0
+		 *
+		 * @param {boolean} enabled Whether On This Day activity is enabled.
+		 * @return {void}
+		 */
+		save_on_this_day_display: function( enabled ) {
+			$.post(
+				ajaxurl,
+				{
+					action: 'on-this-day-display',
+					enabled: enabled ? 1 : 0,
+					screenoptionnonce: $( '#screenoptionnonce' ).val()
+				},
+				function() {
+					wp.a11y.speak(
+						enabled ?
+							__( 'On This Day display is enabled.' ) :
+							__( 'On This Day display is disabled.' )
+					);
+				}
+			);
+		},
+
 		/**
 		 * Saves the order of the postboxes to the server.
 		 *

src/wp-admin/admin-ajax.php

@@ -79,6 +79,7 @@
 	'closed-postboxes',
 	'hidden-columns',
 	'meta-box-reordering',
+	'on-this-day-display',
 	'update-welcome-panel',
 	'menu-get-metabox',
 	'wp-link-ajax',

src/wp-admin/css/dashboard.css

@@ -931,27 +931,28 @@ body #dashboard-widgets .postbox form .submit {
 
 #future-posts ul,
 #published-posts ul,
-#on-this-day-posts ul {
+#wp-on-this-day-posts ul {
 	margin: 8px -12px 0 -12px;
 }
 
 #future-posts li,
 #published-posts li,
-#on-this-day-posts li {
+#wp-on-this-day-posts li {
 	display: grid;
 	grid-template-columns: clamp(160px, calc(2vw + 140px), 200px) auto;
 	column-gap: 10px;
 	color: #646970;
-	padding: 4px 12px;
+	padding: 7px 12px;
+	margin-bottom: 0;
 }
 
 #future-posts li:nth-child(odd),
 #published-posts li:nth-child(odd),
-#on-this-day-posts li:nth-child(odd) {
+#wp-on-this-day-posts-list li:nth-child(odd) {
 	background-color: #f6f7f7;
 }
 
-#on-this-day-posts .wp-on-this-day-post-author {
+#wp-on-this-day-posts-list .wp-on-this-day-post-author {
 	color: #646970;
 }
 
@@ -966,6 +967,13 @@ body #dashboard-widgets .postbox form .submit {
 	margin-bottom: 0;
 }
 
+/* The last visible block, ignoring any hidden blocks that follow it. */
+.activity-block:nth-last-child(1 of :not(.hidden)),
+.no-js .activity-block:nth-last-child(1 of :not(.hidden, .hide-if-no-js)) {
+	border-bottom: none;
+	margin-bottom: 0;
+}
+
 .activity-block .subsubsub li {
 	color: #646970;
 }

src/wp-admin/includes/ajax-actions.php

@@ -1818,6 +1818,22 @@ function wp_ajax_meta_box_reordering() {
 	wp_die( 1 );
 }
 
+/**
+ * Handles the On This Day display setting via Ajax.
+ *
+ * @since 7.2.0
+ *
+ * @return never
+ */
+function wp_ajax_on_this_day_display(): void {
+	check_ajax_referer( 'screen-options-nonce', 'screenoptionnonce' );
+
+	$enabled = isset( $_POST['enabled'] ) && is_string( $_POST['enabled'] ) && '1' === $_POST['enabled'];
+	update_user_option( get_current_user_id(), 'dashboard_show_on_this_day', $enabled ? 'opt-in' : 'opt-out' );
+
+	wp_die( 1 );
+}
+
 /**
  * Handles updating whether to display the welcome panel via AJAX.
  *

src/wp-admin/includes/class-wp-screen.php

@@ -1011,6 +1011,7 @@ public function show_screen_options() {
 
 		if ( $has_meta_boxes ) {
 			$additional_settings .= $this->get_meta_box_reordering_option();
+			$additional_settings .= $this->get_on_this_day_option();
 		}
 
 		if ( 'post' === $this->base ) {
@@ -1184,6 +1185,18 @@ private function get_meta_box_reordering_option() {
 			. '<label for="meta-box-reordering">' . __( 'Allow screen elements to be rearranged' ) . '</label>';
 	}
 
+	/**
+	 * Gets the option to enable or disable meta box reordering.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @return string Meta box reordering option markup.
+	 */
+	private function get_on_this_day_option(): string {
+		return '<input class="wp-on-this-day-toggle" name="wp-on-this-day-toggle" type="checkbox" id="wp-on-this-day-toggle" value="opt-in"' . checked( wp_is_on_this_day_enabled(), true, false ) . ' />'
+			. '<label for="wp-on-this-day-toggle">' . __( 'Display "On This Day" posts in Activity' ) . '</label>';
+	}
+
 	/**
 	 * Checks whether the screen has meta boxes.
 	 *

src/wp-admin/includes/dashboard.php

@@ -1020,6 +1020,25 @@ function wp_dashboard_site_activity() {
  * @return bool False if no posts were found. True otherwise.
  */
 function wp_dashboard_on_this_day( $posts = null ) {
+	if ( 'opt-out' === get_user_option( 'dashboard_show_on_this_day' ) ) {
+		$display_list = false;
+		$display_form = false;
+	} elseif ( 'opt-in' === get_user_option( 'dashboard_show_on_this_day' ) ) {
+		$display_list = true;
+		$display_form = false;
+	} else {
+		/*
+		 * User has not yet chosen to opt-in or -out.
+		 *
+		 * As On This Day features can be distressing in some circumstances,
+		 * users are prompted to opt-in or -out of the feature prior to the
+		 * list of posts being displayed. If they have done neither a form is
+		 * displayed prompting them to make a choice.
+		 */
+		$display_list = false;
+		$display_form = true;
+	}
+
 	if ( null === $posts ) {
 		$posts = wp_dashboard_on_this_day_get_posts();
 	}
@@ -1028,9 +1047,29 @@ function wp_dashboard_on_this_day( $posts = null ) {
 		return false;
 	}
 
-	echo '<div id="on-this-day-posts" class="activity-block">';
-	echo '<h3>' . esc_html__( 'Published On This Day' ) . '</h3>';
-	echo '<ul>';
+	?>
+	<div id="wp-on-this-day-posts" class="activity-block wp-on-this-day-posts-title <?php echo $display_form ? 'hide-if-no-js' : ''; ?> <?php echo ! $display_form && ! $display_list ? 'hidden' : ''; ?>">
+		<h3><?php _e( 'Published On This Day' ); ?></h3>
+	<?php
+
+	if ( $display_form ) :
+		?>
+		<form method="post" id="wp-on-this-day-posts-form">
+		<p>
+			<?php _e( 'Would you like to see posts from previous years here? You can change this later in the Screen Options tab.' ); ?>
+		</p>
+		<p>
+			<?php wp_nonce_field( 'screen-options-nonce', 'screenoptionnonce' ); ?>
+			<button name="enabled" value="1" class="button button-primary"><?php _e( 'Yes' ); ?></button>
+			<button name="enabled" value="0" class="button"><?php _e( 'No' ); ?></button>
+		</p>
+		</form>
+		<?php
+	endif;
+
+	?>
+	<ul id="wp-on-this-day-posts-list" <?php echo $display_list ? '' : 'class="hidden"'; ?>>
+	<?php
 
 	foreach ( $posts as $post ) {
 		/* translators: Date format for posts published in a previous year. */
@@ -1106,13 +1145,32 @@ function wp_dashboard_on_this_day( $posts = null ) {
  * @return WP_Post[] Array of posts ordered by newest first.
  */
 function wp_dashboard_on_this_day_get_posts() {
+	/**
+	 * Filters whether to short-circuit performing the query for the On This Day dashboard query.
+	 *
+	 * Filter to allow the bypassing of the SQL query for the On This Day section of the activity
+	 * widget.
+	 *
+	 * Return null for the default query to run or an array of post IDs to override the built in
+	 * database query. Returning an empty array will have the effect of turning the feature off.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @param WP_Post[]|null $preflight Null to continue, array of post objects to bypass query.
+	 */
+	$preflight = apply_filters( 'pre_wp_dashboard_on_this_day_get_posts', null );
+
+	if ( is_array( $preflight ) ) {
+		return $preflight;
+	}
+
 	$today = current_datetime();
 	$year  = (int) $today->format( 'Y' );
 
 	$args = array(
 		'post_type'              => 'post',
 		'post_status'            => array( 'publish' ),
-		'posts_per_page'         => 10,
+		'posts_per_page'         => 100,
 		'ignore_sticky_posts'    => true,
 		'orderby'                => 'date',
 		'order'                  => 'DESC',

src/wp-admin/includes/screen.php

@@ -207,6 +207,19 @@ function wp_is_meta_box_reordering_enabled() {
 	return false === $setting ? true : 'disabled' !== $setting;
 }
 
+/**
+ * Determines whether On This Day display is enabled.
+ *
+ * @since 7.2.0
+ *
+ * @return bool Whether meta box reordering is enabled.
+ */
+function wp_is_on_this_day_enabled(): bool {
+	$setting = get_user_option( 'dashboard_show_on_this_day' );
+
+	return 'opt-in' === $setting;
+}
+
 /**
  * Register and configure an admin screen option
  *